Direction of Based Death Animation

[jackisawesome3]

I'm currently working on a 2D zombie shooter style game and I can't figure out how to make it so that when a bullet hits a zombie in the front of their head, the animation that plays the blood comes out of the back. Right now, any time you kill an enemy, the animation shows blood coming out of the back of the head plays so it looks really weird when I shoot an enemy from behind. Does anyone know what to do?

Thanks For All Help!

[Notice] Yes, I messed up with the title. It should say "Direction Based Death Animation"

[casleziro]

For a simple solution that doesn't require math;

Ditch the animation and instead make the blood active objects that move around or just a single animated active you can rotate.

Whenever a bullet hits a zombie, you would create your blood particles and make them move in the direction the bullet was, or you create your animated blood object and rotate it to the direction the bullet was traveling.